Box blank having integral frame for removable cover



April 16, 1968 P. THOMPSON 3,373,186

BOX BLANK HAVING INTEGRAL FRAME FOR REMOVABLE COVER Filed May 51, 1966 FIG.

PA UL THOMPSON 1 NVENTOR.

J; ma

ATTORNEYS United States Patent 0 3,378,186 BOX BLANK HAVING INTEGRAL FRAME FOR REMOVABLE COVER Paul Thompson, Wellesley, Mass., assignor to Bestpak, Inc., Naticlr, Mass, a corporation of Massachusetts Filed May 31, 1966, Ser. No. 554,142 4 Claims. (Cl. 229-44) ABSTRACT OF THE DISCLOSURE This invention is a box, and blank therefor, of the folding window box type made of paper board. A single unitary box blank is provided having walls which may be folded upward to form the box bottom portion, these walls having flaps attached to their upward edges which may be folded downwardly to provide the enclosing walls of a cover portion, the construction of the upwardly and downwardly extending walls being such that a sheet of transparent plastic may be stretched over the opening of the thus folded structure to provide a box top, the plastic being attached solely to the outer surfaces of the dependent flaps. Along at least three of the edges where the flaps join the upstanding bottom walls, perforations are provided so that the flaps may be torn loose from the upstanding walls, and when so separated the flaps and the plastic sheet comprise a cover for the remaining por tion of the box hinged along the fourth edge.

This invention is concerned with folding boxes especially of paperboard, and with the paperboard blanks of which they are constructed. It deals principally with window boxes, i.e. boxes having transparent covers through which merchandise contained in the box can be inspected. Its principal object is to provide a single unitary box blank of which the box and the frame for a removable transparent cover can be simultaneously fabricated by simple folding operations.

As merchandising on the basis of self-service by the customer continues to become an ever increasing factor in our economy, so does the importance of efficiency in each phase of the process. One phase of the process is the packing of perishable goods, e.g., fruits, vegetables, cakes, and the like in containers that may be so arranged on shelves that the purchaser can readily inspect the contents, viewing them through a transparent window in the container and may, after making a purchase, utilize the container as a package for transportation and temporary storage of the purchased goods.

To secure these results, window boxes of various kinds have been developed. Each leaves something to be desired. Thus, if the box proper is fabricated of a single blank, packed with the goods to be displayed and thereafter covered with transparent sheet material such as cellophane, the purchaser must break the window to reach the goods, in which case she has no cover for the box. To avoid this inconvenience to the purchaser it has become common to fabricate the box of one blank and the box cover, with an inserted transparent window, if another blank. Such a cover can be removed from the box and replaced at will. However, to provide adequate support for the transparent window, the cover normally has, at each margin, an inwardly extending opaque portion which interferes with the purchasers view of the contents. Independent fabrication of two components, namely, the box proper and its window cover, naturally increases cost. Moreover, whatever decision the fabricator may have made as to whether the cover shall be hinged to the box or nowhere attached to it, the purchaser may have a different view.

These various problems are solved at one stroke by the box blank of this invention which gives greater visibility and greater economy in materials used. and construction. In this invention, in addition to the customary rectangular bottom portion, side portions, end portions and cornersecuring tabs, four auxiliary flap portions are provided which are attached at their inner margins to the outer margins of the side and end portions of the box. At least three of the four auxiliary flaps are attached by creases that are generously perforated, i.e., cut through along the greater part of their lengths, leaving only small threadlike bridges by which the flaps are attached to the sides and ends of the box. In the process of folding the box and securing its corners, which operations are usually performed by machine, these auxiliary flaps hang downward from the upper margins of the ends and sides of the box and outside of them. Advantageo-usly, the flaps are of slightly greater lengths than the sides and ends to which they are attached. This ensures that they shall not accidentally hang inside of the box.

The box having been constructed by folding and securing its corners, it is next packed with the goods to be displayed for sale. It is then overlaid with a sheet of flexible transparent, and preferably thermoplastic, material, for

example, cellophane, of area somewhat greater than that of the open face of the box, and the skirts of this sheet are folded downwardly over the sides and ends of the box and are secured, for example by heating to the softening point, not to the ends and sides of the box proper but only to the auxiliary flaps. The box, thus filled and covered, is now placed on display. No opaque material in the plane of the transparent cover interferes with the purchasers view of its contents. After purchasing the box and taking it home with her the purchaser can, if she wishes, set it aside until it is needed without fear of damage to the contents. When she wishes to remove the contents from the box the purchaser has only to exert a small lifting force on the lower margin of one of the flaps. By virtue of the generous perforation of the crease by which this flap is attached to the end or side of the box, the threadlike bridges which remain uncut are torn and the window cover, now framed by at least three of the flaps and perhaps all four of them, rises in the purchasers hand. If the creases by which the flaps are attached to the sides and ends of the box are all similarly perforated, the entire cover is removed. It can, moreover, be replaced at any time since, by virtue of the frame provided by the flaps, now torn from the box, it is sufficiently rigid to retain its shape. Especially if the flaps are slightly longer than the ends and sides of the box, e.g., by at least twice the thickness of the paperboard, the cover continues to fit easily over the box when replaced on it.

Because the fabricator of the box can never anticipate the wishes of the purchaser with complete assurance (he never knows whether the purchaser will wish to remove the cover entirely or to leave it hinged to the box) it is a further feature of the invention that, while the uncut bridges by which three of the flaps are: attached are weak enough to be very easily torn, those by which the fourth auxiliary flap is attached are substantially stronger. With this arrangement the lifting force initially exerted tears the cover from the box along the three generously perforated creases, leaving the fourth one untorn. The cover is now hinged to the box, and may remain so hinged until the contents of the box have been consumed. But, by

exerting a slightly greater force, the purchaser can also tear the fourth auxiliary flap from the side or end to which it is attached thus, in effect, breaking the hinge and having, in one hand, an open box and, in the other, a transparent window cover which fits over it.

The invention will be fully apprehended from the following detailed description of an illustrative embodiment thereof taken in connection with the appended drawing, in which:

FIG. 1 is a plan view of a box blank embodying the invention; and

FIG. 2 is a perspective view of a box constructed of the blank of FIG. 1, with its cover partially removed.

Referring now to the drawings, FIG. 1 shows a paperboard box blank constructed in accordance with the invention. It comprises the usual rectangular bottom portion 1, the two usual rectangular side portions 2, 3 and the two usual rectangular end portions 4-, 5, each attached to the bottom portion 1 by a folding crease F. At the corners are tabs 6, 7, for holding the finished box in shape, each bounded by a folding crease F and a cut C. Advantageously, the lines along which the cuts C are made follow largely diagonal courses, thus to provide, hinged to the ends 4, 5 of the box, triangular tabs which mate with the sides 2, 3 of the box and, similarly, hinged to the sides 2, 3 of the box triangular tabs which mate with the ends 4, 5 of the box. This construction provides rigidity against forces which might distort or tear the box in either of two perpendicular directions. To avoid the awkwardness which attends an attempt to fold paperboard exceedingly close to an acute angle, the diagonal cuts C may extend from each outer corner nearly but not quite to the opposite inner corner and then turn, first through an angle of 45 in one sense and then through a right angle in the opposite sense. The box may, of course, also use more conventional types of setup construction such as the single, conventional glued flap, lockstyle or even tapered nesting construction.

In addition to the bottom, the sides, the ends and the corner tabs, FIG. 1 shows auxiliary flaps 8, attached at their inner margins to the outer margins of the side portions 2, 3 and other auxiliary flaps 10, 11 attached at their inner margins to the outer margins of the end portions 4, 5. The length of each flap is greater by two or three times the thickness of the paperboard than the length of the side or end to which it is attached. In the case of both sides and one end the attachment is by way of bridges or threads, the remainder of the attachment lines P P P being cut through. These bridges or threads are of the order of wide and are spaced apart by an inch or two. Advantageously, no bridge or thread is left immediately adjacent to any end of any one of the auxiliary flaps. Rather, the line of attachment is cut through the full thickness of the paperboard at least for a major fraction of an inch at each end of each attachment line. This is in order that the initial lifting force applied by the purchaser to the lower edge of the auxiliary fiap, e.g., at one corner of the covered box, shall be concentrated, first at the nearest bridge and then, when this has been torn, at the next bridge, and so on until all the bridges have been torn.

The line of attachment P of the auxiliary flap 11 to the end 5 of the box is characterized by less generous perforations than that described above for the other three attachment lines. (The attachment may be along the side instead of the end.) Thus, for example, for each inch of length of this attachment line R; the through cut may extend for A to leave bridges of the order of A1" in width. The attachment of this auxiliary flap 11 is thus about four times as strong as are the attachments of the three other auxiliary flaps. Thus the purchaser, if she wishes, can easily tear along three of the perforated lines, while refraining from tearing along the fourth. This leaves her with a transparent hinged cover, shown partway open in FIG. 2. If, to the contrary, she wishes to remove the cover entirely she can still do so by exerting a somewhat greater force to tear along the fourth perforated line P The box having been constructed by folding and securing its corners, packed with the goods to be displayed for sale, and overlaid with a sheet 12 of cellophane, the skirts of this sheet are folded downwardly over the sides and ends of the box and are secured to the auxiliary flaps 8- 11. The box, thus filled and covered, is now ready for display, purchase, storage or immediate opening as described above.

A minor auxiliary problem may arise when the line of attachment P of the fourth auxiliary flap is to serve as a hinge in that unless care is exercised to provide freedom of unfolding of the folded corners of the cellophane cover skirt, these folded corners may impede rotation of the cover about the hinge. This may be avoided in various ways. One way is to make the seals at the two corners of the box adjacent the ends of the hinge line so light that the adhesive will break when gently pulled. Alternatively, the skirt of the cellophane cover at these corners can be nicked or scored in such a way that, when the cover is rotated about the hinge, the cellophane skirts will themselves tear. Still better, each bellows formed by folding the cellophane cover at a corner of the box may be folded inwardly; i.e., tucked under a side or end portion of the cellophane skirt, and the sealing may be restricted to locations where a single thickness of cellophane is in direct contact with a side or end flap, thus ensuring that there shall be no adhesion between juxtaposed faces of the folded bellows. With this arrangement, when the cover is lifted and rotated about the hinge line, the bellows located at each end of the hinge line expands and unfolds by itself and interposes no resistance to the rotation.

The inward folding of the bellows may be facilitated by arranging that the cellophane skirt depend somewhat further below one of the flaps, for example the hinge flap, than it extends below the other flaps.

The invention having now been described, what is claimed is:

1. A box blank of sheet material which comprises a rectangular bottom portion bounded by end creases and side creases; end portions bounded at their inner margins by said end creases; and side portions bounded at their inner margins by said side creases whereby, said bottom portion lying in a horizontal plane, said end and side portions are adapted to be bent into substantially vertical planes, thus to form a box of rectangular crosssection; means for securing the ends of said end portions to the ends of said side portions to provide strength and rigidity to the box; and auxiliary flaps attached along the outer margins of the end and side portions by auxiliary creased portions, said flaps being adapted to hang downwardly from the upper margins of said end and side portions and outside the box when the latter is formed. the lengths of said auxiliary flaps being in excess of the lengths of said end and side portions to which they are attached; and at least three of said auxiliary creased portions being perforated, whereby when a box is made from said blank and is overlaid with transparent sheet material that is secured only to the outer surfaces of the auxiliary flaps, exertion of a small lifting force on the lower margin of one of said auxiliary flaps operates to tear the perforated creased portions, whereby to provide the user of the box with a removable box cover of which the top is constituted of said transparent material while the frame is constituted of said auxiliary flaps.

2. A box blank as defined in claim 1 wherein the length dimensions of the auxiliary flaps exceed the length dimensions of the end and side portions to which they are attached by at least twice the thickness dimension of the sheet material of which the blank is constructed whereby, when the perforated creases are torn to provide a transparent cover for the box, the dimensions of the cover sufficiently exceed the dimensions of the box that the cover, once removed from the box, is readily replaced thereon.

3. A rectangularly shaped box having a bottom and four upwardly extending walls attached thereto; downwardly extending flaps integrally connected to the perimeter of three of the walls by folds, the folds being perforated to provide tearable attachments of the flaps with said three of the walls; and a sheet of transparent plastic overlaying all of the Walls and flaps thereby to provide a cover for the box, the sheet being attached solely to the outer surfaces of the flaps, whereby when the flaps are separated from their respective walls, the flaps and the sheet form a top cover for the box, the flaps forming the walls of the top cover, the sheet forming the top, and the top cover being hinged to the fourth of said upstanding walls.

4. The box of claim 3 in which the lengths of said flaps exceed the lengths of said upstanding walls by at least twice the thickness of the material of which the box is constructed.

References Cited UNITED STATES PATENTS 2,071,949 2/1937 Reich 229-3] 2,474,523 6/1949 Guyer 229--37 3,040,877 6/1962 Chidsey 20645.31 3,193,174- =6/1965 Glasband et a] 229-3l X 3,273,302 9/1966 Walter 20645.33 X

DAVID M. BOCKENEK, Primary Examiner. 

